Our long-term goal is to understand behavior and social interactions as processes of adaptation to the problems that individuals face in their natural environment. The research is carried out on free-ranging primates, primarily the baboon population of the Amboseli Reserve, Kenya, which is the subject of a series of ongoing studies by the P.I. and his colleagues. Research to be undertaken during the next five years includes both field studies of primates, and research on theory and analysis of primate social systems and ecology. The projects are as follows: (1) Demography and group dynamics. (2) Infant feeding behavior and malnutrition. (3) Ergonomics of behavior. (4) Attention, maternal care, and infant development. (5) Foraging behavior and resource depression. (6) Differential home range utilization. (7) Kinship and group geometry. (8) Status stability and differential reproduction. (9) The evolution of mating systems. (10) Monographic synthesis. BIBLIOGRAPHIC REFERENCES: Altmann, J., S. Altmann, G. Hausfater & S. McCuskey 1976, Life cycle of yellow baboons: infant mortality, physical development, and reproductive parameters. Primates, in press. Altmann, S. 1976, Baboon progressions: order or chaos? A study of one-dimensional group geometry. Anim. Behav., in press.